This invention relates to a method of increasing the width of a band of voltages associated with a particular identification code as the voltages themselves increase.
The present invention is specifically directed to a disclosed system wherein an identification voltage is associated with particular types of fuel injectors to provide a control feedback on characteristics of those fuel injectors. A series of distinct voltages are associated with different combinations of two characteristics. The control can read an electric signal which is influenced by the voltages, and can thus identify the particular combination of characteristics. One problem with this type of system is the reduction or elimination of identification errors. Thus, it would be desirable to minimize the occurrences of when a particular monitored voltage is associated with a particular set of characteristics by the control, but wherein the injector actually possesses a different set of characteristics than that which the control has identified.
A number of different factors can influence the occurrence of such errors. As an example, a disclosed embodiment utilizes resistors to provide the coding identification voltages. Of course, as with any manufactured items, there are tolerances within the resistors. Thus, the resistors themselves can result in errors in the voltage. Moreover, the voltage source which drives the entire system may also vary from the predicted voltage source values, which can also result in errors.
It is has been found that when errors in the voltage source occur, the errors are effectively almost proportional to the voltage. Further, when the errors are due to an error in the resistance in the resistors being utilized to provide the identification voltage, the error is almost proportional to the voltage.
As the voltages associated with codes increase, and as the number of codes themselves increase, the possible errors thus also increase. As the possible error increases, the likelihood of a misreading error also increases if the differences between the voltage associated with adjacent codes are equally spaced.
While the invention is disclosed with regard to voltage identification of codes for use in identifying characteristics of fuel injectors, any system which utilizes an increasing voltage as an identification code for particular characteristics can benefit from this invention. In fact, any system which has an increasing variable for identifying a plurality of codes, be it voltage or some other variable, will benefit from this invention.